NCBI C++ ToolKit
platform_util.c
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1 /*
2  * Common and shared functions used by multiple modules in the Mbed TLS
3  * library.
4  *
5  * Copyright The Mbed TLS Contributors
6  * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
7  */
8 
9 /*
10  * Ensure gmtime_r is available even with -std=c99; must be defined before
11  * mbedtls_config.h, which pulls in glibc's features.h. Harmless on other platforms
12  * except OpenBSD, where it stops us accessing explicit_bzero.
13  */
14 #if !defined(_POSIX_C_SOURCE) && !defined(__OpenBSD__)
15 #define _POSIX_C_SOURCE 200112L
16 #endif
17 
18 #if !defined(_GNU_SOURCE)
19 /* Clang requires this to get support for explicit_bzero */
20 #define _GNU_SOURCE
21 #endif
22 
23 #include "common.h"
24 
25 #include "mbedtls/platform_util.h"
26 #include "mbedtls/platform.h"
27 #include "mbedtls/threading.h"
28 
29 #include <stddef.h>
30 
31 #ifndef __STDC_WANT_LIB_EXT1__
32 #define __STDC_WANT_LIB_EXT1__ 1 /* Ask for the C11 gmtime_s() and memset_s() if available */
33 #endif
34 #include <string.h>
35 
36 #if defined(_WIN32)
37 #include <windows.h>
38 #endif
39 
40 // Detect platforms known to support explicit_bzero()
41 #if defined(__GLIBC__) && (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 25)
42 #define MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO 1
43 #elif (defined(__FreeBSD__) && (__FreeBSD_version >= 1100037)) || defined(__OpenBSD__)
44 #define MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO 1
45 #endif
46 
47 #if !defined(MBEDTLS_PLATFORM_ZEROIZE_ALT)
48 
49 #undef HAVE_MEMORY_SANITIZER
50 #if defined(__has_feature)
51 #if __has_feature(memory_sanitizer)
52 #include <sanitizer/msan_interface.h>
53 #define HAVE_MEMORY_SANITIZER
54 #endif
55 #endif
56 
57 /*
58  * Where possible, we try to detect the presence of a platform-provided
59  * secure memset, such as explicit_bzero(), that is safe against being optimized
60  * out, and use that.
61  *
62  * For other platforms, we provide an implementation that aims not to be
63  * optimized out by the compiler.
64  *
65  * This implementation for mbedtls_platform_zeroize() was inspired from Colin
66  * Percival's blog article at:
67  *
68  * http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html
69  *
70  * It uses a volatile function pointer to the standard memset(). Because the
71  * pointer is volatile the compiler expects it to change at
72  * any time and will not optimize out the call that could potentially perform
73  * other operations on the input buffer instead of just setting it to 0.
74  * Nevertheless, as pointed out by davidtgoldblatt on Hacker News
75  * (refer to http://www.daemonology.net/blog/2014-09-05-erratum.html for
76  * details), optimizations of the following form are still possible:
77  *
78  * if (memset_func != memset)
79  * memset_func(buf, 0, len);
80  *
81  * Note that it is extremely difficult to guarantee that
82  * the memset() call will not be optimized out by aggressive compilers
83  * in a portable way. For this reason, Mbed TLS also provides the configuration
84  * option MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure
85  * mbedtls_platform_zeroize() to use a suitable implementation for their
86  * platform and needs.
87  */
88 #if !defined(MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO) && !(defined(__STDC_LIB_EXT1__) && \
89  !defined(__IAR_SYSTEMS_ICC__)) \
90  && !defined(_WIN32)
91 static void *(*const volatile memset_func)(void *, int, size_t) = memset;
92 #endif
93 
94 void mbedtls_platform_zeroize(void *buf, size_t len)
95 {
96  if (len > 0) {
97 #if defined(MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO)
98  explicit_bzero(buf, len);
99 #if defined(HAVE_MEMORY_SANITIZER)
100  /* You'd think that Msan would recognize explicit_bzero() as
101  * equivalent to bzero(), but it actually doesn't on several
102  * platforms, including Linux (Ubuntu 20.04).
103  * https://github.com/google/sanitizers/issues/1507
104  * https://github.com/openssh/openssh-portable/commit/74433a19bb6f4cef607680fa4d1d7d81ca3826aa
105  */
106  __msan_unpoison(buf, len);
107 #endif
108 #elif defined(__STDC_LIB_EXT1__) && !defined(__IAR_SYSTEMS_ICC__)
109  memset_s(buf, len, 0, len);
110 #elif defined(_WIN32)
111  SecureZeroMemory(buf, len);
112 #else
113  memset_func(buf, 0, len);
114 #endif
115 
116 #if defined(__GNUC__)
117  /* For clang and recent gcc, pretend that we have some assembly that reads the
118  * zero'd memory as an additional protection against being optimised away. */
119 #if defined(__clang__) || (__GNUC__ >= 10)
120 #if defined(__clang__)
121 #pragma clang diagnostic push
122 #pragma clang diagnostic ignored "-Wvla"
123 #elif defined(MBEDTLS_COMPILER_IS_GCC)
124 #pragma GCC diagnostic push
125 #pragma GCC diagnostic ignored "-Wvla"
126 #endif
127  asm volatile ("" : : "m" (*(char (*)[len]) buf) :);
128 #if defined(__clang__)
129 #pragma clang diagnostic pop
130 #elif defined(MBEDTLS_COMPILER_IS_GCC)
131 #pragma GCC diagnostic pop
132 #endif
133 #endif
134 #endif
135  }
136 }
137 #endif /* MBEDTLS_PLATFORM_ZEROIZE_ALT */
138 
139 void mbedtls_zeroize_and_free(void *buf, size_t len)
140 {
141  if (buf != NULL) {
143  }
144 
145  mbedtls_free(buf);
146 }
147 
148 #if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
149 #include <time.h>
150 #if !defined(_WIN32) && (defined(unix) || \
151  defined(__unix) || defined(__unix__) || (defined(__APPLE__) && \
152  defined(__MACH__)) || defined__midipix__)
153 #include <unistd.h>
154 #endif /* !_WIN32 && (unix || __unix || __unix__ ||
155  * (__APPLE__ && __MACH__) || __midipix__) */
156 
157 #if !((defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L) || \
158  (defined(_POSIX_THREAD_SAFE_FUNCTIONS) && \
159  _POSIX_THREAD_SAFE_FUNCTIONS >= 200112L))
160 /*
161  * This is a convenience shorthand macro to avoid checking the long
162  * preprocessor conditions above. Ideally, we could expose this macro in
163  * platform_util.h and simply use it in platform_util.c, threading.c and
164  * threading.h. However, this macro is not part of the Mbed TLS public API, so
165  * we keep it private by only defining it in this file
166  */
167 #if !(defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)) || \
168  (defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR))
169 #define PLATFORM_UTIL_USE_GMTIME
170 #endif
171 
172 #endif /* !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) || \
173  ( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) && \
174  _POSIX_THREAD_SAFE_FUNCTIONS >= 200112L ) ) */
175 
176 struct tm *mbedtls_platform_gmtime_r(const mbedtls_time_t *tt,
177  struct tm *tm_buf)
178 {
179 #if defined(_WIN32) && !defined(PLATFORM_UTIL_USE_GMTIME)
180 #if defined(__STDC_LIB_EXT1__)
181  return (gmtime_s(tt, tm_buf) == 0) ? NULL : tm_buf;
182 #else
183  /* MSVC and mingw64 argument order and return value are inconsistent with the C11 standard */
184  return (gmtime_s(tm_buf, tt) == 0) ? tm_buf : NULL;
185 #endif
186 #elif !defined(PLATFORM_UTIL_USE_GMTIME)
187  return gmtime_r(tt, tm_buf);
188 #else
189  struct tm *lt;
190 
191 #if defined(MBEDTLS_THREADING_C)
192  if (mbedtls_mutex_lock(&mbedtls_threading_gmtime_mutex) != 0) {
193  return NULL;
194  }
195 #endif /* MBEDTLS_THREADING_C */
196 
197  lt = gmtime(tt);
198 
199  if (lt != NULL) {
200  memcpy(tm_buf, lt, sizeof(struct tm));
201  }
202 
203 #if defined(MBEDTLS_THREADING_C)
204  if (mbedtls_mutex_unlock(&mbedtls_threading_gmtime_mutex) != 0) {
205  return NULL;
206  }
207 #endif /* MBEDTLS_THREADING_C */
208 
209  return (lt == NULL) ? NULL : tm_buf;
210 #endif /* _WIN32 && !EFIX64 && !EFI32 */
211 }
212 #endif /* MBEDTLS_HAVE_TIME_DATE && MBEDTLS_PLATFORM_GMTIME_R_ALT */
213 
214 #if defined(MBEDTLS_TEST_HOOKS)
215 void (*mbedtls_test_hook_test_fail)(const char *, int, const char *);
216 #endif /* MBEDTLS_TEST_HOOKS */
217 
218 #if defined(MBEDTLS_HAVE_TIME) && !defined(MBEDTLS_PLATFORM_MS_TIME_ALT)
219 
220 #include <time.h>
221 #if !defined(_WIN32) && \
222  (defined(unix) || defined(__unix) || defined(__unix__) || \
223  (defined(__APPLE__) && defined(__MACH__)) || defined(__HAIKU__) || defined(__midipix__))
224 #include <unistd.h>
225 #endif \
226  /* !_WIN32 && (unix || __unix || __unix__ || (__APPLE__ && __MACH__) || __HAIKU__ || __midipix__) */
227 #if (defined(_POSIX_VERSION) && _POSIX_VERSION >= 199309L) || defined(__HAIKU__)
229 {
230  int ret;
231  struct timespec tv;
232  mbedtls_ms_time_t current_ms;
233 
234 #if defined(__linux__) && defined(CLOCK_BOOTTIME) || defined(__midipix__)
235  ret = clock_gettime(CLOCK_BOOTTIME, &tv);
236 #else
237  ret = clock_gettime(CLOCK_MONOTONIC, &tv);
238 #endif
239  if (ret) {
240  return time(NULL) * 1000;
241  }
242 
243  current_ms = tv.tv_sec;
244 
245  return current_ms*1000 + tv.tv_nsec / 1000000;
246 }
247 #elif defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
248  defined(__MINGW32__) || defined(_WIN64)
249 #include <windows.h>
251 {
252  FILETIME ct;
253  mbedtls_ms_time_t current_ms;
254 
255  GetSystemTimeAsFileTime(&ct);
256  current_ms = ((mbedtls_ms_time_t) ct.dwLowDateTime +
257  ((mbedtls_ms_time_t) (ct.dwHighDateTime) << 32LL))/10000;
258  return current_ms;
259 }
260 #else
261 #error "No mbedtls_ms_time available"
262 #endif
263 #endif /* MBEDTLS_HAVE_TIME && !MBEDTLS_PLATFORM_MS_TIME_ALT */
#define NULL
Definition: ncbistd.hpp:225
unsigned int
A callback function used to compare two keys in a database.
Definition: types.hpp:1210
char * buf
int len
#define mbedtls_platform_gmtime_r
#define mbedtls_mutex_lock
#define mbedtls_mutex_unlock
This file contains the definitions and functions of the Mbed TLS platform abstraction layer.
#define mbedtls_free
Definition: platform.h:166
int64_t mbedtls_ms_time_t
Definition: platform_time.h:35
mbedtls_ms_time_t mbedtls_ms_time(void)
Get time in milliseconds.
time_t mbedtls_time_t
Definition: platform_time.h:27
static void *(*constvolatile memset_func)(void *, int, size_t)
Definition: platform_util.c:91
void mbedtls_zeroize_and_free(void *buf, size_t len)
Securely zeroize a buffer then free it.
void mbedtls_platform_zeroize(void *buf, size_t len)
Securely zeroize a buffer.
Definition: platform_util.c:94
Common and shared functions used by multiple modules in the Mbed TLS library.
Threading abstraction layer.
Modified on Mon Jul 15 05:36:39 2024 by modify_doxy.py rev. 669887